Over-wintering Tropical Waterlilies

When over-wintering tropical waterlilies, you’ll find success with any of the following methods. We’ve successfully used them all, and even other variations of them. Use what you find convenient, or try a couple of different methods and see what works best for you.

To maximize their size and bloom, tropical waterlilies should be planted into large pots at least 12” in diameter. They should be fertilized heavily once warm weather has arrived and the plant is growing vigorously (2 to 4 times as much as hardy lilies). If you want to induce dormancy and form a hard over-wintering tuber, restrict fertilizing two months before frosts begin to allow the plant to use up available fertilizer and prepare itself for dormancy. If dormancy is successfully induced, the plant will produce a smaller, hard tuber different and separate from its normal root structure. This tuber is hard and dense enough that it is not easily crushed between thumb and forefinger, almost like a nut.

Method 1:

It is good for the lilies to go through 1 or 2 frosts.  The cool weather helps force dormancy.  After the first or second frost remove the plants from the pond. Put the pots in a cool but protected place, such as the garage and let the pots dry out somewhat until the soil is barely moist. Wrap each pot in a garbage bag and close the top of the bag so they don’t dry out further, but do not tightly close the top; this way it can breathe just a little.

Put them somewhere in the house, garage or basement with a consistently cool temperature of 55-60 degrees (for viviparous tropicals, those which can produce new plantlets out of the leaf, 60-65 degrees is better). When spring comes, take them out and put them back in the pond when water temperatures reach 65 degrees or more. They may also be forced in heated water in direct sunlight or with plant lights. Low wattage submersible aquarium heaters work great when used with an aquarium or whiskey barrel size liner (keep the heater off the plastic!).

Method 2:

Again, it is good for the lilies to go through 1 or 2 frosts. Take each tuber out of the pot and gently clean it off (spraying off with normal water pressure is okay, but do not scrub). Trim off any roots and leaves; you may leave any tiny new submerged leaves, if present.  Place each tuber in a sealed sandwich bag or glass jar, with or without a little fungicide, and cover it with water. Put them somewhere in the house, garage or basement with a consistently cool temperature of 55-60 degrees (for viviparous tropicals, those which can produce new plantlets out of the leaf, 60-65 degrees is better). You can use a glass jar without a lid, and put the jar on a cool but not cold windowsill. In the spring you may place each tuber into a 3-4” pot with soil and ½ -1 tab of fertilizer; use 65+ degree water in direct sunlight or with plant lights. Once the waterlily fills out the starter pot you may transfer it to a gallon or 8”x5” pot. 

Method 3:

The waterlilies should go through 1 or 2 frosts. Take each tuber out of the pot and gently clean it off (spraying off with normal water pressure is okay, but do not scrub). Trim off any roots and leaves. Gently towel dry and pack each tuber in damp, almost dry sand (with or without a fungicide powder) inside a sandwich bag or glass jar. The sand should be dried out to the moisture level of pipe tobacco. Put them somewhere in the house, garage or basement with a consistently cool temperature of 55-60 degrees (for viviparous tropicals, those which can produce new plantlets out of the leaf, 60-65 degrees is better).  They should be left in darkness for a few months to keep them dormant. In the spring, follow the above directions.

Article supplied by Oregon Aquatics, Inc. and Southwest Aquatics, LLC.